Now I have added colors!

Update of my project

import pygame, sys

pygame.init()
screen = pygame.display.set_mode((1366, 768))
box = pygame.Rect(2.5, 2.5, 5, 5)

while True:
    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            sys.exit(0)
        elif event.type == pygame.KEYDOWN and event.key == pygame.K_ESCAPE:
            sys.exit(0)
        elif event.type == pygame.KEYDOWN and event.key == pygame.K_SPACE:
            screen.fill((0, 0, 0))

    if pygame.key.get_pressed() [pygame.K_d]:
        box.x += 1
    if pygame.key.get_pressed() [pygame.K_a]:
        box.x -= 1
    if pygame.key.get_pressed() [pygame.K_w]:
        box.y -= 1
    if pygame.key.get_pressed() [pygame.K_s]:
        box.y += 1


    if pygame.key.get_pressed() [pygame.K_b]:
        pygame.draw.rect(screen,(3, 252, 248), box)

    if pygame.key.get_pressed() [pygame.K_g]:
        pygame.draw.rect(screen,(53, 252, 3), box)

    if pygame.key.get_pressed() [pygame.K_r]:
        pygame.draw.rect(screen,(252, 3, 3), box)
    
    pygame.display.flip()